The opening verse of the īśāvāsya Upaniṣad is one of the most quoted and least understood verses in the Indian tradition. It is also one of the shortest.
īśā vāsyam idaṃ sarvaṃ yat kiñca jagatyāṃ jagat |
tena tyaktena bhuñjīthā mā gṛdhaḥ kasya svid dhanam ||
All this—whatever moves in the moving world—is to be clothed by the Lord.
By that renunciation, take your enjoyment. Covet not anyone's wealth.
Word by word.
īsā (īśा)—instrumental of īsa, "Lord", "ruler". The Lord here is not anthropomorphic. It is the all-pervading reality, that which rules from within.
vāsyam (वास्यम्)—gerundive of vas, "to clothe" or "to dwell in". The double sense is critical and probably intentional. Either the world is to be clothed in the Lord (the Lord covers everything) or the Lord is to be dwelt in everything (the Lord pervades everything from within). The grammar permits both. The non-dualist tradition argues both are saying the same thing.
idam sarvam (इदं सर्वम्)—"all this". Indicates the immediate phenomenal world. Not "everything in some abstract sense". This. What is in front of you.
yat kiñca jagatyāṃ jagat—"whatever moves in the moving world". The repetition is deliberate. Jagat (from jagaṅ, "to move") literally means "that which moves". The verse says: in the moving thing, whatever moves. Reality is dynamic all the way down.
tena tyaktena bhuñjīthāḥ—"by that renunciation, enjoy". The instrumental tena tyaktena is famously ambiguous. Is it "by that (which is) renounced"? Or "through renunciation, by means of that"? Śaṅkara takes it the second way. The renunciation is itself the means of enjoyment.
mā gṛdhaḥ kasya svid dhanam—"do not covet anyone's wealth". Or, with a different reading of kasya svid: "whose, after all, is wealth?" The double sense is again likely deliberate. Do not covet; and also: nothing belongs to anyone in the first place.
What the verse is doing.
It is establishing a way of being in the world that is neither acquisitive nor world-denying. The Lord pervades everything; therefore everything is sacred. Because everything is sacred, nothing can be owned. Because nothing can be owned, enjoyment is possible only through renunciation—through letting go of the grasping that turns the sacred into property.
This is not asceticism. The verse explicitly says: enjoy. Bhuñjīthāḥ. It is the same root as bhoga, "enjoyment". The verse is not telling you to abstain. It is telling you what right relation to enjoyment looks like.
The whole of the dharmic ethical tradition—from the Bhagavadgītā's teaching of karmayoga through to the medieval Tamil saint-poets' insistence that the world is the body of God—is in some sense an unpacking of these eight words.
The verse is two and a half thousand years old. It does not need a single addition.